I. For the purposes of this Schedule -- 

      (a) the average load factor of a station shall be expressed as a percentage, and shall be ascertained by multiplying the number of kilwatt-hours supplied from the station during the year of account by 100, and dividing the product so obtained by the product of the average monthly maximum demand multiplied by the number of hours during which the station was in commission in the year of account; 

      (b) the average monthly maximum demand shall be the arithmetical average of the monthly maximum demands on the station in those calendar months during which the station was in commission in the year of account; 

      (c) a station shall be deemed to be in commission when the whole or any portion of the plant in the station is generating electricity of is in readiness to generate electricity upon demand. 

      (d) “cost of fuel” means the sums expended for fuel consumed plus the cost of any transport, handling, preparation or treatment incurred in connection with the delivery of fuel to the boiler hoppers, furnaces or engines and in connection with the disposal of the products or residues of combustion, plus the proportion of salaries and wages and any contributions made by the owner of the station for pensions, provident fund, superannuation and insurance of officers and servants properly attributable to such delivery or disposal, less any sums received from the sale of any products or residues of combustion; 

      (e) “cost of oil, water and stores” means the sum expended for oil, water and stores consumed; 

      (f) “cost of repairs, maintenance and renewals” means the sums expended for repairs and maintenance and for renewals not chargeable to capital account together with the proportion of salaries and wages and any contributions made by the owner of the station for pensions, provident fund, superannuation and insurance of ²[officers and other employees] properly attributable to repairs, maintenance  and renewals; 

      (g) “salaries and wages” means the sums expended for salaries and wages and any contributions made by the owner of the station for pensions, provident fund, superannuation and insurance of officers and servants, less the proportion of such sums properly attributable to the cost of fuel under clause(d) & to the cost of repairs, maintenance and renewals under clause(f)